The Radiochemistry and Instrumentation Support Laboratory (RISL) is one of the core facilities and shared resources of The Ohio State University (OSU) Comprehensive Cancer Center (CCC). The purposes of the RISL are fivefold: (1) to provide custom synthesis of radiochemicals not available commercially to investigators of the OSUCCC, (2) to perform purification of custom preparations of chemically-labile radiochemicals, (3) to aid in the purchase of radiochemicals, advice on the use of radiochemical products and equipment, and provide radiation safety expertise to the CCC, (4) to provide organic chemical support services [synthesis, isolation, structure determination, chemistry expertise] for CCC investigators, and (5) to maintain chemical instrumentation for the isolation and structure determination of carcinogens, drugs, metabolites, and biochemical compounds and general equipment for biochemical/biological research. Robert W. Brueggemeier, Ph.D. is director of the Radiochemistry and Instrumentation Support Laboratory and is involved with projects both as a shared resource person and as a principal investigator within he OSUCCC. Michael V. Darby, Ph.D. serves as the full-time synthetic radiochemist in the Radiochemistry Laboratory. Drs. Brueggemeier and Darby co-direct a graduate research assistant and work closely with cost doctoral research and technicians on the various projects utilizing radiochemistry and chemistry services. Several research and service activities were expanded or introduced since July 1995. These additional services include development of methods of determination of 8-hydroxydeoxyguanosine levels by HPLC- electrochemical detection, expansion of iodination procedures using a variety of reagents, acquisition and installation of new instrumentation and relocation of instruments into laboratory facilities where the instruments are more effectively utilized. The RISL will continue to be an effective radiochemistry and instrumentation support facility for cancer research, diagnosis, or treatment that is encompassed in the OSU Comprehensive Cancer Center.